Left home alone for the weekend, two sisters navigate their strained rivalry amid the horrors of adolescent sexuality. Lizzy Sanford writes and directs “The Knot,” an understated character study about sibling-hood and teenage rites of passage. The film is merely a glimpse but it’s painted with vision and nuance, insinuating larger struggles to come (from our interview with Sanford: “This film was intended to be a testing ground for these sister characters I've been writing in a feature script.”) Sanford has a keen sense of the rhythms and attitudes of sisters, largely characterized here with petty arguments — Beth’s toast is getting crumbs all over the bed; she’s stretching out Fiona’s shirt by wearing it. Meanwhile Fiona’s experience with boys intrigues Beth as she begins to explore her own sexuality. Tess McMillan playing the younger sister is perfectly curious and ‘on edge’ about the new world around her, while Fiona, played by Anna Cordell (who previously starred in Sanford’s “Rubber Heart”) exudes a brash confidence yet capable of leveling down as she senses her sister’s vulnerabilities. -KA. Writer, director: Lizzy Sanford. Starring: Anna Cordell, Tess McMillan, Keith Poulson. Director of Photography: Eli Born. Editor: Lizzy Sanford. Producer: Neighborhood Watch. Sound: Sal Barra. Gaffer: Kevin Phillips.